Flow cytometry has historically been performed with general purpose instruments designed to allow for a wide range of applications. Flow cytometers function by passing cells in a single file line, under ideal circumstances, through one or more laser interrogation points. Scattered and/or emitted light is then collected and filtered at specific wavelengths and converted to an electrical signal representative of the intensity of the light at those specific wavelengths. The properties of the detected signal are measured and information regarding the cell is used to make a sort decision. User selected criteria is utilized to make a sort decision. The user selected criteria defines gates for selection of events within a histogram. Complex logic, including multiple parameters and histograms, additional regions and gates and cascaded gates allow users to specify which cells are to be sorted. This process of user defined regions to perform sorting processes is referred to as region classification. In that regard, if an event (a cell) falls within one or more regions and, in some cases, in or not in other regions on a histogram, sort logic is used to determine cells of interest.